How Should We Decide Whom to Imprison?

Incarceration is sometimes necessary to protect the safety of the public. But how can we ensure that these decisions are fair? How can we tell if someone truly poses a danger to others?

Judges, police, and other justice system professionals make these decisions every day. However, studies demonstrate that it is difficult to accurately predict who will be violent — even for experts.

During the past 30 years, scientists have been working to improve these judgments by developing decision-making aids called risk assessment instruments. These instruments tell professionals which risk factors to consider in deciding how to supervise and treat people who have been charged with crimes.

Hundreds of studies show that these instruments help to identify people who pose the highest risk for violence. Accordingly, justice agencies in the United States, Canada, and other countries now routinely use risk assessment instruments with more than a million people each year.

Advocates argue that these instruments may help divert defendants who are not dangerous from prison, thereby minimizing the overuse of incarceration. This is important because the United States currently imprisons more people than any place in the world, and this has proven to be expensive and unsustainable.

However, critics are concerned that these instruments might exacerbate preexisting racial and ethnic disparities in incarceration due to inherent biases.

In a paper published in Law and Human Behavior (2019), psychologists Jodi Viljoen and Gina Vincent test these assertions.

Viljoen and Vincent, along with colleagues Melissa Jonnson, Dana Cochrane, and Lee Vargen, aggregated studies that compared imprisonment rates when risk assessment instruments were and were not used.

Through a systematic review of the research, they identified 22 studies that included more than a million people who were charged with or convicted of a crime. They then compiled the results by conducting a meta-analysis and a narrative review.

Their results show that after justice agencies adopt risk assessment instruments, there are small but significant declines in rates of pretrial detention and increases in postconviction release.

In addition, even though imprisonment rates decrease, crime rates do not increase. Instead, crime rates either stay the same or decrease slightly.

This indicates that it may be possible to decrease rates of imprisonment without jeopardizing public safety. Instead of incarcerating everyone, the key may be to detain only those who are truly dangerous.

Although the results provide tentative support for the assertion that risk assessments may reduce detention rates, the authors emphasize that much of the research in this area is poor in quality. Furthermore, most studies did not include information on how risk assessment instruments affect racial and ethnic disparities in incarceration.

The studies that did examine disparities found that when instruments were used, incarceration rates decreased for people of color. However, findings varied as to whether the size of this decrease was similar for people of color and White people.

Before we can draw clear conclusions, more rigorous research is urgently needed.

Citation

• Viljoen, J. L., Jonnson, M. R., Cochrane, D. M., Vargen, L. M., & Vincent, G. M. (2019). Impact of risk assessment instruments on rates of pretrial detention, postconviction placements, and release: A systematic review and meta-analysis. Law and Human Behavior, 43(5), 397–420. https://dx.doi.org/10.1037/lhb0000344

Note: This article is in the Forensic Psychology topic area. View more articles in the Forensic Psychology topic area.

Jodi Viljoen, PhD, is a professor of clinical and forensic psychology at Simon Fraser University, an associate director of the Institute for the Reduction of Youth Violence, and the coordinator for the Law and Forensic Psychology Program at Simon Fraser University.

She has held grants from the Social Sciences and Humanities Council of Canada, Canadian Institutes for Health Research, and the Michael Smith Foundation for Health Research for studies on assessing and treating risk of violence and offending.

Gina Vincent, PhD, is an associate professor at the Implementation Science and Practice Advances Research Center, and co-director of the Law and Psychiatry Program at the University of Massachusetts Medical School.

Dr. Vincent has received funding from the National Institute of Mental Health, the National Institute on Drug Abuse, the MacArthur Foundation, and the Office of Juvenile Justice and Delinquency Prevention for studies relevant to risk for reoffending, mental health symptoms, and substance abuse among youth involved in the juvenile justice system.

She is author of the widely-used Risk Assessment in Juvenile Probation: A Guidebook for Implementation manual.